Cartridge flash hole inspection apparatus

ABSTRACT

An apparatus for inspecting the number and capacity of vent or flash holes in a cartridge case having an optical tester to count the vent holes and pass a case upon detection of a minimum number of vent holes and an air flow tester for directing a measured flow of air through the vent holes of cartridge cases passed by the optical tester to detect the capacity thereof and pass the cartridge case upon detection of a capacity within predetermined limits.

United States Patent Christensen June 5, 1973 CARTRIDGE FLASH HOLEINSPECTION APPARATUS Inventor: George L. Christensen, Los Ange-1es,Calif.

Assignee: Martin Marietta Aluminum lnc.,

Torrance, Calif. Filed: Sept. 15, 1971 Appl. No.: 180,789

US. Cl ..73/38, 73/167 Int. Cl ..G0ln 15/08 Field of Search ..73/38, 40,49.2,

References Cited UNlTED STATES PATENTS Dixon ..73/49.2

Primary Examiner-Donald O. Woodiel AttorneyMil1en, Raptes 8L White 57ABSTRACT An apparatus for inspecting the number and capacity of vent orflash holes in a cartridge case having an optical tester to count thevent holes and pass a case upon detection of a minimum number of ventholes and an air flow tester for directing a measured flow of airthrough the vent holes of cartridge cases passed by the optical testerto detect the capacity thereof and pass the cartridge case upondetection of a capacity within predetermined limits.

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INVIZN'IOI GEORGE L. .CHRISTENSEN ATTORNEYS 1 CARTRIDGE FLASH HOLEINSPECTION APPARATUS BACKGROUND OF THE INVENTION Due to theconfiguration of the cup, case and vent holes as described above,reliable inspection of the vent holes is difficult on a mass productionbasis in that it is impossible to pass a direct line-of-sight inspectionthrough the holes and awkward to inspect the vent holes with evenoblique, indirect viewing. Such difficulty is even further complicatedby the criticality of not only the capacity of openings but the numberor distribution thereof. At their optimum, the vent holes not only havethe capacity for communication of a predetermined amount of propellantpressure to the low pressure chamber but are distributed forcommunication of that pressure in a symmetrical pattern such that flighttransjectory of the grenade is within close limits. As the fabricationof the vent holes deviates from the optimum, either in capacity or innumber or distribution, the proper functioning of the ammunition isjeopardized to a degree which is a function of the amount of deviation.It is, therefore, a requirement of inspection that the vent holes notonly be inspected for capacity but also be inspected for distributionand/or number. In other words, through a malfunction during fabrication,the propellant cup may have openings therethrough of sufficientaggregate size to satisfy the capacity requirements and yet thedistribution or number thereof may be insufficient to satisfy thepressure distribution requirement or, conversely, the number of ventholes may be sufficient to satisfy the distribution requirement but theaggregate size of the holes may not be within the limits dictated by thecapacity requirement.

SUMMARY OF THE INVENTION This invention proves an inspection apparatuswhich accurately and reliably inspects vent holes in cartridge cases forcompliance with both capacity and distribution requirements byfurnishing tests for both number and capacity of the vent holes.

The invention further provides an apparatus which inspects the numberand capacity factors of cartridge case vent holes by furnishing anoptical scanner for counting the flash holes and a fluid, preferably agas and most preferably air, pressure application for measuring thecapacity thereof.

This invention further provides a novel optical scanner for use in acartridge case inspection apparatus which provides for inspection ofradially oriented vent openings wholly within the case by furnishing alight source simultaneously directed radially through each of the flashholes, a light receiving scanner disposed to sequentially receive lightthrough each of the holes and a counter to count light impulses receivedduring scanning.

In a preferred embodiment, this invention provides an apparatus forinspecting the number and capacity of vent holes in a cartridge casehaving an optical tester to count the vent holes and pass a case uponthe detection of a minimum number of flash holes and a gas tester fordirecting a gas, preferably air, through the vent holes of cartridgecases passed by the optical tester to measure the gas-flow capacitythereof and pass the cartridge case upon detection of a capacity withinpredetermined limits.

These and other advantages of the invention will become betterunderstood by those skilled in the art by reference to the followingdetailed description when viewed in light of the accompanying drawingswherein like numerals indicate like components throughout the figuresand wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an apparatusembodying the teachings of this invention;

FIG. 2 is an elevational view of the apparatus of FIG.

FIG. 3 is a fragmentary perspective view of the optical testing portionof the apparatus of FIG. 1;

FIGS. 4 and 5 are fragmentary sectional views taken through the opticaltesting portion of the apparatus of FIG. 1 showing sequences ofoperation thereof;

FIGS. 6 and 7 are enlarged fragmentary elevational views in section ofportions of the apparatus shown in FIG. 2;

FIG. 8 is an enlarged sectional view taken through the gas pressuretesting of the apparatus of FIG. 1;

FIG. 9 is an enlarged sectional view similar to FIGS. 6 and 7 showinganother portion of the apparatus of FIG. 2; and

FIG. 10 is a schematic view of the operating mechanism of the apparatusof FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIGS. 1 and 2, the apparatuscomprises generally a feeder bowl 10 which communicates with aninspection track 12 to feed a series of cartridge cases to be inspected14 thereto in a manner known in the art.

The track 12, is provided, intermediate the ends thereof, with anoptical testing station and a gas pressure testing station, showngenerally at 16 and 18 respectively. The track 12 is also provided,depending therebeneath, with cartridge case reject chutes 20, 22 and 24which serve to receive and channel cartridges rejected by the testingstations.

The chute 20, located immediately downstream of the optical testingstation 16, communicates with the track 12 through a trap door 26 whichis actuated by door-actuating cylinder 28 upon signal from the opticaltesting station 16 as will be described in detail hereinbelow. Thecylinder 28, as well as similar actuating cylinders to be describedhereinbelow, is preferably pneumatically powered; however, the cylindersmay be hydraulically, electrically or otherwise driven if so desired.

The chutes 22 and 24, located downstream of the fluid pressure testingstation 18, communicate with the track 12 through trapdoors 30 and 32,respectively, which doors are identically actuated by solenoids 34 and36, respectively, through linkages shown schematically at 38. Thelinkage 38, connected to a hinge arm 40 for the trapdoor 30, operates tomove the trapdoor upwardly as shown in phantom to deflect cartridgecases having, for example, a capacity tested by the gas pressure tester18 less than that required for reliable operation while the 'door 32 isidentically deflected by energization of the solenoid 36 to deflectcartridge cases testing over capacity. Cartridges within the capacitylimitations of the apparatus continue out of the lower end of the track12.

With reference to the optical testing station or portion 16 and withparticular reference to FIG. 3, the portion comprises a base support 42disposed beneath the track 12, to which a slide block 44 is fixed andslide 46 is mounted in the block 44 and supports a prism holder 48which, in turn, rotatably supports a prism mount 50. The prism mount 50has, coaxially disposed thereon, a gear or pinion 52 which meshes with arack 54] which rack is driven by a pneumatic cylinder 56. Microswitches53 and 55 are positioned to operate as reset switches for purposes to bedescribed below. The rack 54 and cylinder 56 are mounted to move withthe slide 46 which, in turn, is driven toward and away from the track 12by a pneumatic cylinder 58 mounted on the base 42. The sidewall of thetrack 12 has, formed therethrough, an opening 60 to receive the prismmount 50 when extended therethrough and with which a cartridgecase-to-be-inspected can be registered as will be described below.

Mounted on the opposite side of the track 12 is a light source 62 whichis extendable into the track through an opening 64 in the wall of thetrack by a pneumatic cylinder 66 connected thereto by a rod 68. Theabove-described assembly is supported by means ofa bracket 70 attachedto the sidewall of the track 12. As is best seen by reference to FIGS. 1and 2, at its innermost travel, the light source 62 engages amicroswitch 72 with an arm 74 mounted on the light source to provide forsequencing as will be described in greater detail below.

Disposed above the optical testing portion 16, a platform 76 supports avertical cylinder 78 and stop cylinder 80 which vertically extend andretract a spacer 82 and a stop 84, respectively, to and from blockingpositions in the track 12.

With more particular reference to FIGS. 4 and 5, the operation of theoptical testing station can be seen. The light source comprises a lampand holder assembly 86 and a cylindrical mount 88 having a 360 mirror 90disposed around the end thereof. The mirror 90 is disposed to directlight rays from the lamp assembly 86 radially inwardly normal to thecentral axis of the mount 88.

The prism mount 50 has an optical prism 92 mounted on the end thereofwhich is adapted to direct light rays normal to the axis of the mount 88received thereby, parallel to the axis of the prism mount 50. The mount50 comprises a hollow tube 94 for transmitting light from mirror 90 to aphotocell or the like (not shown) from which signals are analyzed bymeans well known in the art such as, for example, a solid state counterutilizing RTL logic (not shown).

A series of air flow switches 96a, 96b, 96c and 96d are disposed alongthe track 12 to sense the presence of cartridges at selected points forpurposes to be described below.

In operation, as thus far described, cartridges 14 are fed from therotary feeder bowl 10 into the track 12 until a sufficient number havecollected to interrupt air flow at air flow switch 96a whereupon powerto the feed bowl is shut off by suitable control means (not shown). Thecylinder initially extends the spacer 82 to preclude cartridges fromentering the optical inspection station 16. With the cylinder extendingthe stop 84 into blocking position, the cylinder 78 retracts the spacer82 on command from a sequence timer to be described below, allowing thefirst of the cartridges 14 to enter the station 16 under the influenceof gravity and come to rest against the stop 84. The spacer 82 is thenextended to block the next succeeding cartridge.

The light source 62 is then inserted into the cartridge 14 (FIG. 5) byextension of the cylinder 66, thereby exposing the 360 mirror to directlight from the lamp assembly 86 radially inwardly through a series ofvent holes 96 within the cartridge case 14. As was set forth above, theinward movement of the light source 62 also causes the arm 74 to engageand close the microswitch which, through circuitry to be describedbelow, extends cylinder 58 to insert the prism mount 50 into theopposite end of the cartridge 14 and position the prism 92 inwardly ofthe vent holes 96. The sequence timer then commands cylinder 56 toextend, thereby rotating the mount 50 to cause the prism 92 to scan thevent holes 90 and by release of the reset switch 53, to start thecounter for light pulses received through the prism mount.

Light transmitted through vent holes 96 is sequentially transmitted as alight pulse through tube 94 to the photocell and a portion or all of thepulses are counted. At the end of the stroke of the rack 54, the switch55 is closed for actuation of the door actuating cylinder 28 if aninsufficient number of pulses are received by the counter during thestroke of the rack54. Upon retraction of the rack 54, the reset switch53 is closed resetting the counter for the next cycle.

The cylinder 80 is then retracted by the sequence timer and thecartridge case tested is allowed to roll toward the gas pressure testingstation 18. If the number of vent holes counted by the optical testingstation 16 is below the minimum number required, the trapdoor 26 isopened as described above and held open by a time delay switch and thatcartridge is diverted into the chute 20.

If the cartridge is acceptable, it enters the gas pressure testingstation 18, passing under a positioner 98 extendable into the track bycylinder 100 mounted thereabove on a platform 101. A stop 102, spaceddownstream from the positioner 98, is similarly extended onto the track12 by a cylinder 104.

With particular reference now to FIG. 8, the gas pressure testingstation 18 comprises a pressure chamber 106 disposed on one side of thetrack 12 and a ram 108 driven by a cylinder 110 disposed on the otherside of the track. The chamber 106 is provided with a testing orifice112 and a fluid supply inlet 114. An O-ring seal 116 is disposed in anannular recess around the orifice 112. The assembly is mounted on asupport platform 118 from which an air gauge 120 depends. The air gaugeis of a type known in the art, such as, for example, an air gaugemarketed under .the trademark Ames," which can be set to provide anelectrical impulse to signal under and over pressure conditions. The

gauge 120 communicates with the chamber 106 and serves to monitor theback pressure therein.

In operation, with a cartridge case 14 against the stop 102, thesequence timer extends the cylinder 100 to bring the positioner 98 downon the cartridge. The sequence timer then commands the cylinder 110 toextend, extending the ram 108 to press the face of the cartridge 14against the chamber 106 so that a fluid seal is provided by the O-ring116 (FIG. 8). Air then flows out of the chamber 106, as shown by arrowsin FIG. 8, through the vent holes 96 in the cartridge 14. Since theaggregate size or capacity of the vent holes is a function of the backpressure in the chamber 106 as determined by the resistance to air flowthrough the vent holes 96, the pressure in the chamber is an accurateindicator of the capacity of the vent holes. By proper setting of theair gauge 120, under and over capacity signals can be generated when thevent hole capacity of the tested cartridge is beyond desired tolerances. During the above test, the sequence timer provides anenergization to the solenoids 34 and 36 which are wired to open eitherthe trap door 30 or 32 if an under capacity or over capacity signal,respectively, is generated by the air gauge 120. If neither signal isgenerated, then neither door is opened. If either one of the doors 30 or32 is opened, time delay relays hold them open until the testedcartridge is released and enters the open door. The sequence timer thenretracts cylinder 104 to allow the tested cartridge 14 to roll down thetrack 12 whereupon the cartridge is deflected by open door 30 or 32 intothe chutes 22 or 24 (FIG. 9) if over or under capacity signals,respectively, have been generated by the air gauge 120, or if thecartridge is acceptable, to be discharged from the end of the track 12.The air flow switches 96b, 96c and 96d are positioned along the track 12at points where, if cartridges back up to interrupt the flow thereby dueto a malfunction of the apparatus, the apparatus will be deenergized toprovide for clearing of the mechanism.

In FIG. 10, a schematic of the system is illustrated. The sequencetimer, referred to above, comprises a series of rotary cams 120 whichsequentially operate corresponding switches 122 to open and closecircuits providing electrical power through conductors 123 to solenoidvalves V controlling pneumatic pressure to the various pneumaticcylinders for the apparatus in the order and according to the programset forth above.

Pneumatic pressure is supplied to the system through a manifold 124 froman air supply tank 126 at a pressure determined by pressure regulators128. The air is transmitted through pneumatic conduits to the valves Vfor the respective cylinders where the pressure is directed to thecylinder according to the energized or deenergized condition of thatvalve in a manner known in the art.

A counter 132, of a type referred to above, is connected to the prismholder 48 by means of a conductor 134 and serves to energize the valve Vfor the cylinder 28 to open the trapdoor 26 if the count from the prismis less than that required as was disclosed above.

Electrical power for the apparatus is provided by a power source 136.

What is new and desired to be protected by Letters Patent of the UnitedStates is: V

1. Apparatus for inspecting the number and capacity of vent holes in acartridge case comprising:

optical means to count the number of vent holes and pass said cartridgecase upon detection of a minimum number of openings;

gas pressure means for directing a gas stream through said vent holes insaid cartridge cases to detect the aggregate capacity of said vent holesthereof as a function of back pressure and pass said case upon detectionof a back pressure within predetermined limits; and

means to transport said passed cases from one of said optical means andsaid fluid or air pressure means to the other.

2. Apparatus according to claim 1 wherein said passed cases aretransported from said optical means to said gas means.

3. An apparatus in accordance with claim 1 wherein said gas or airpressure means comprises a pressure chamber including an outlet orificeregisterable with the flash holes in said cartridge case, means to holdsaid cartridge case in fluid-tight relationship with said outletorifice, a source of gas pressure communicative with said chamber and agas pressure gauge means for detecting the pressure in said chamber.

4. An apparatus in accordance with claim 3 wherein said means to holdsaid cartridge comprises a reciprocable ram insertable in said cartridgeto positively hold said cartridge.

5. An apparatus in accordance with claim 1 wherein said means totransmit comprises a track disposed at an angle with the horizontal.

1. Apparatus for inspecting the number and capacity of vent holes in acartridge case comprising: optical means to count the number of ventholes and pass said cartridge case upon detection of a minimum number ofopenings; gas pressure means for directing a gas stream through saidvent holes in said cartridge cases to detect the aggregate capacity ofsaid vent holes thereof as a function of back pressure and pass saidcase upon detection of a back pressure within predetermined limits; andmeans to transport said passed cases from one of said optical means andsaid fluid or air pressure means to the other.
 2. Apparatus according toclaim 1 wherein said passed cases are transported from said opticalmeans to said gas means.
 3. An apparatus in accordance with claim 1wherein said gas or air pressure means comprises a pressure chamberincluding an outlet orifice registerable with the flash holes in saidcartridge case, means to hold said cartridge case in fluid-tightrelationship with said outlet orifice, a source of gas pressurecommunicative with said chamber and a gas pressure gauge means fordetecting the pressure in said chamber.
 4. An apparatus in accordancewith claim 3 wherein said means to hold said cartridge comprises areciprocable ram insertable in said cartridge to positively hold saidcartridge.
 5. An apparatus in accordance with claim 1 wherein said meansto transmit comprises a track disposed at an angle with the horizontal.